From: Konstantin Khlebnikov <khlebnikov@openvz.org>
To: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Matt Helsley <matthltc@us.ibm.com>,
Oleg Nesterov <oleg@redhat.com>
Subject: [PATCH v2 09/10] mm: kill mm->num_exe_file_vmas and keep mm->exe_file until final mmput()
Date: Sat, 07 Apr 2012 23:01:33 +0400 [thread overview]
Message-ID: <20120407190133.9726.26191.stgit@zurg> (raw)
In-Reply-To: <20120407185546.9726.62260.stgit@zurg>
exe_file's vma accouning is hooked into every file mmap/unmmap and vma
split/merge just to fix some hypothetical pinning fs from umounting by mm,
which already unmapped all its executable files, but still alive.
Seems like currently nobody depends on this behaviour.
We can try to remove this logic and keep mm->exe_file until final mmput().
mm->exe_file is still protected with mm->mmap_sem, because we want to change it
via new sys_prctl(PR_SET_MM_EXE_FILE) in future. Also via this syscall task can
change its mm->exe_file and unpin mountpoint explicitly.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
---
include/linux/mm.h | 3 ---
include/linux/mm_types.h | 1 -
kernel/fork.c | 21 ---------------------
mm/mmap.c | 27 +++++----------------------
mm/nommu.c | 14 ++------------
5 files changed, 7 insertions(+), 59 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8e82b79..3a4d721 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1373,9 +1373,6 @@ extern void exit_mmap(struct mm_struct *);
extern int mm_take_all_locks(struct mm_struct *mm);
extern void mm_drop_all_locks(struct mm_struct *mm);
-/* From fs/proc/base.c. callers must _not_ hold the mm's exe_file_lock */
-extern void added_exe_file_vma(struct mm_struct *mm);
-extern void removed_exe_file_vma(struct mm_struct *mm);
extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
extern struct file *get_mm_exe_file(struct mm_struct *mm);
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 3cc3062..b480c06 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -378,7 +378,6 @@ struct mm_struct {
/* store ref to file /proc/<pid>/exe symlink points to */
struct file *exe_file;
- unsigned long num_exe_file_vmas;
#ifdef CONFIG_MMU_NOTIFIER
struct mmu_notifier_mm *mmu_notifier_mm;
#endif
diff --git a/kernel/fork.c b/kernel/fork.c
index 2e060c8..54662ed 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -587,26 +587,6 @@ void mmput(struct mm_struct *mm)
}
EXPORT_SYMBOL_GPL(mmput);
-/*
- * We added or removed a vma mapping the executable. The vmas are only mapped
- * during exec and are not mapped with the mmap system call.
- * Callers must hold down_write() on the mm's mmap_sem for these
- */
-void added_exe_file_vma(struct mm_struct *mm)
-{
- mm->num_exe_file_vmas++;
-}
-
-void removed_exe_file_vma(struct mm_struct *mm)
-{
- mm->num_exe_file_vmas--;
- if ((mm->num_exe_file_vmas == 0) && mm->exe_file) {
- fput(mm->exe_file);
- mm->exe_file = NULL;
- }
-
-}
-
void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
{
if (new_exe_file)
@@ -614,7 +594,6 @@ void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
if (mm->exe_file)
fput(mm->exe_file);
mm->exe_file = new_exe_file;
- mm->num_exe_file_vmas = 0;
}
struct file *get_mm_exe_file(struct mm_struct *mm)
diff --git a/mm/mmap.c b/mm/mmap.c
index bc67ed7..2647bb7 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -230,11 +230,8 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
might_sleep();
if (vma->vm_ops && vma->vm_ops->close)
vma->vm_ops->close(vma);
- if (vma->vm_file) {
+ if (vma->vm_file)
fput(vma->vm_file);
- if (vma->vm_file == vma->vm_mm->exe_file)
- removed_exe_file_vma(vma->vm_mm);
- }
mpol_put(vma_policy(vma));
kmem_cache_free(vm_area_cachep, vma);
return next;
@@ -616,11 +613,8 @@ again: remove_next = 1 + (end > next->vm_end);
mutex_unlock(&mapping->i_mmap_mutex);
if (remove_next) {
- if (file) {
+ if (file)
fput(file);
- if (file == mm->exe_file)
- removed_exe_file_vma(mm);
- }
if (next->anon_vma)
anon_vma_merge(vma, next);
mm->map_count--;
@@ -1293,8 +1287,6 @@ munmap_back:
error = file->f_op->mmap(file, vma);
if (error)
goto unmap_and_free_vma;
- if (file == mm->exe_file)
- added_exe_file_vma(mm);
/* Can addr have changed??
*
@@ -1969,11 +1961,8 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
if (anon_vma_clone(new, vma))
goto out_free_mpol;
- if (new->vm_file) {
+ if (new->vm_file)
get_file(new->vm_file);
- if (new->vm_file == mm->exe_file)
- added_exe_file_vma(mm);
- }
if (new->vm_ops && new->vm_ops->open)
new->vm_ops->open(new);
@@ -1991,11 +1980,8 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
/* Clean everything up if vma_adjust failed. */
if (new->vm_ops && new->vm_ops->close)
new->vm_ops->close(new);
- if (new->vm_file) {
- if (new->vm_file == mm->exe_file)
- removed_exe_file_vma(mm);
+ if (new->vm_file)
fput(new->vm_file);
- }
unlink_anon_vmas(new);
out_free_mpol:
mpol_put(pol);
@@ -2377,11 +2363,8 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
new_vma->vm_start = addr;
new_vma->vm_end = addr + len;
new_vma->vm_pgoff = pgoff;
- if (new_vma->vm_file) {
+ if (new_vma->vm_file)
get_file(new_vma->vm_file);
- if (new_vma->vm_file == mm->exe_file)
- added_exe_file_vma(mm);
- }
if (new_vma->vm_ops && new_vma->vm_ops->open)
new_vma->vm_ops->open(new_vma);
vma_link(mm, new_vma, prev, rb_link, rb_parent);
diff --git a/mm/nommu.c b/mm/nommu.c
index db8da78..d617d5c 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -789,11 +789,8 @@ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
kenter("%p", vma);
if (vma->vm_ops && vma->vm_ops->close)
vma->vm_ops->close(vma);
- if (vma->vm_file) {
+ if (vma->vm_file)
fput(vma->vm_file);
- if (vma->vm_file == mm->exe_file)
- removed_exe_file_vma(mm);
- }
put_nommu_region(vma->vm_region);
kmem_cache_free(vm_area_cachep, vma);
}
@@ -1287,10 +1284,6 @@ unsigned long do_mmap_pgoff(struct file *file,
get_file(file);
vma->vm_file = file;
get_file(file);
- if (file == current->mm->exe_file) {
- added_exe_file_vma(current->mm);
- vma->vm_mm = current->mm;
- }
}
down_write(&nommu_region_sem);
@@ -1441,11 +1434,8 @@ error:
if (region->vm_file)
fput(region->vm_file);
kmem_cache_free(vm_region_jar, region);
- if (vma->vm_file) {
+ if (vma->vm_file)
fput(vma->vm_file);
- if (vma->vm_file == vma->vm_mm->exe_file)
- removed_exe_file_vma(vma->vm_mm);
- }
kmem_cache_free(vm_area_cachep, vma);
kleave(" = %d", ret);
return ret;
--
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next prev parent reply other threads:[~2012-04-07 19:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-07 19:00 [PATCH v2 00/10] mm: vma->vm_flags diet Konstantin Khlebnikov
2012-04-07 19:00 ` [PATCH v2 01/10] x86, pat: remove the dependency on 'vm_pgoff' in track/untrack pfn vma routines Konstantin Khlebnikov
2012-04-07 19:01 ` [PATCH v2 02/10] x86, pat: separate the pfn attribute tracking for remap_pfn_range and vm_insert_pfn Konstantin Khlebnikov
2012-04-07 19:01 ` [PATCH v2 03/10] mm, x86, pat: rework linear pfn-mmap tracking Konstantin Khlebnikov
2012-04-07 19:01 ` [PATCH v2 04/10] mm: introduce vma flag VM_ARCH_1 Konstantin Khlebnikov
2012-04-07 19:01 ` [PATCH v2 05/10] mm: kill vma flag VM_CAN_NONLINEAR Konstantin Khlebnikov
2012-04-20 10:52 ` Nick Piggin
2012-04-07 19:01 ` [PATCH v2 06/10] mm: kill vma flag VM_INSERTPAGE Konstantin Khlebnikov
2012-04-07 19:01 ` [PATCH v2 07/10] mm: use mm->exe_file instead of first VM_EXECUTABLE vma->vm_file Konstantin Khlebnikov
2012-04-07 19:21 ` Chris Metcalf
2012-04-07 19:01 ` [PATCH v2 08/10] mm: kill vma flag VM_EXECUTABLE Konstantin Khlebnikov
2012-04-07 19:01 ` Konstantin Khlebnikov [this message]
2012-04-07 19:01 ` [PATCH v2 10/10] mm: move madvise vma flags to the end Konstantin Khlebnikov
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